The field of the disclosure relates generally to ducted fans, and, more particularly, to a ducted fan that includes an inlet with a variable geometry.
At least some known aircraft have engines that include ducted fans. At least some known ducted fans include an inlet with a fixed geometry. For example, the inlet geometry is selected to facilitate enhanced performance for an expected operational mode of the ducted fan. However, at least some known aircraft, such as some known vertical takeoff and landing (“VTOL”) aircraft, include at least two distinct operational modes, such as a hover mode and a high-speed cruise mode, that have conflicting inlet geometry performance requirements. As a result, selecting a fixed inlet geometry that facilitates enhanced performance in each mode is difficult.
At least some known ducted fans are provided with a variable geometry inlet. The geometry is designed to vary between a first geometry, which facilitates enhanced performance in a first operational mode of the fan, and a second geometry, which facilitates enhanced performance in a second operational mode of the fan. However, a mechanical and/or control complexity of at least some known variable geometry inlets limits a reliability, cost effectiveness, and performance of such known variable geometry ducted fans.